Many vehicles such as farm implements and earthmoving equipment have governor regulated engines. The governor is usually employed to establish normal operating speed and maximum power output of the engine. The governor of some such vehicles is provided with a variable governor control with which the power setting of the governor is automatically adjusted in response to drive ratio selection in the transmission. One such arrangement is disclosed in U.S. Pat. No. 3,554,059 issued to John H. Parks et al on Jan. 12, 1971.
One of the problems with such arrangement is that no means is provided to optimize the lug characteristic or torque rise for each of the power settings of the governor. This could result in inefficient burning of the fuel which might cause the emission of noxious exhaust emissions and smoke from the engine at one or more of the power settings. Torque rise is defined as the inherent increase in the output torque of the engine when the engine speed decreases from the full load or other preselected speed due to increased loading on the engine.